What is a pressurised liquid nitrogen dewar and when should a laboratory use one instead of an open-neck storage vessel?
A pressurised liquid nitrogen dewar – also referred to as a liquid nitrogen cylinder or supply dewar – is a sealed vessel designed to hold liquid nitrogen under controlled pressure, typically between 0.5 and 1.7 bar, to enable controlled dispensing of liquid nitrogen into smaller vessels without direct manual handling. Unlike open-neck storage dewars, which vent continuously to atmosphere, pressurised dewars use an internal pressure-building circuit to raise the liquid to dispensing pressure through a dip tube. The liquid nitrogen exits as a controlled stream that can be directed into cryogenic storage vessels or controlled rate freezers.
The key operational decision point is volume throughput. Laboratories topping up a small number of storage dewars infrequently can use manual ladles or flexible transfer hoses from open-neck supply vessels safely. Facilities with high liquid nitrogen consumption – busy IVF units, large biobanks, or sperm banks running multiple filling cycles per day – benefit from pressurised dispensing systems that reduce manual handling time and exposure risk. Cryolab supplies liquid nitrogen dispensing equipment including the CryoCrest range, alongside the cryogenic PPE required for safe dispensing operations. Contact us to specify the right dispensing solution for your facility’s throughput.
